.swi
{	
	 width:5em;
	 position:relative;
	 height:1.625em;
	 overflow:hidden;
	 -webkit-transition: all 200ms linear;
	 transition: all 200ms linear;
}
.swi-bg {
	background-image:url('switch/on-off.png');
	background-size:auto 100%;
	background-repeat:no-repeat;
	background-origin:border-box;
	
}

input[type=checkbox]:checked + div.swi{
 	background-position:-0.1em;
}

input[type=checkbox] + div.swi
{
	background-position:-3.01em
}